Suresh,

Regarding modeling Pipe shoes in C-II, which could be done using a rigid element from the center till the BOP of pipe, and then putting the restraint at that node. This could be done for large diameter pipe above 24" because the support will not be at the center. C-2 being a beam element software does not understand the concept of shell. There are various problems associated with this method.
1. When the pipe passes through a reducer to a smaller pipe size, the length of the rigid element will vary and will cause non uniform load distribution on a straight run of pipe. The C-2 results will be different..
2. There will be additional moments due to guide or friction at the center of pipe due to shoe, if the diameters are large i.e say 42"
3. The rigid element will experience thermal expansion, and problems of lift off will be seen in adjacent supports for a high temperature piping.

You will have more problems while analysing a system with large diameters....
I had done this on a system with 90" diameter, temp=500 Deg.C and landed into problems on support load distribution and hence stresses. We do not know about the correct load distribution at site for large diameter piping. We assume the results from C-2 output are accurate. But I am still not confident on this.

The best way to model is to assume the support at the center of pipe and check the shoe for loads using FE software.

Regards,

Suraj